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Characteristics of turf herbicides

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In turf management, the two most basic categories of herbicides are preemergence and postemergence. Preemergence materials are applied preventively, that is prior to germination, to control weeds that have not yet appeared. Postemergence materials are applied to existing, actively growing weeds.  Some herbicides have both preemergence and postemergence activity. With such materials, appropriate application timing can be dictated by the target weed(s), distinct characteristics of the herbicide, or specific management goals.

Herbicides can be more finely categorized into chemical classes, which indicate the mode or mechanism of action of each compound. The particular mode of action influences whether a material is effective against broadleaf weeds, grassy weeds, or a more specific collection of species. Many individual modes of action offer selective control of weeds within desirable turf, while others provide non-selective control more appropriate for spot treatment and renovation situations.

Refer to Table 12 below to cross reference trade names with active ingredients.

Table 11. Characteristics of turf herbicide active ingredients registered for use in Massachusetts.

amicarbazone

Chemical class Mode of action Application timing
triaolinone inhibits photosynthesis postemergence

Controls annual bluegrass, crabgrass, bittercress, carpetweed, henbit, field pennycress, common chickweed, sticky chickweed, Virgina pepperweed, purslane, shepherd’s-purse, spurge, and oldfield toadflax.

benefin

Chemical class Mode of action Application timing
dinitroaniline interferes with cell division preemergence

Controls crabgrass, goosegrass, annual bluegrass, yellow foxtail and many annual broadleaf weeds.

bensulide

Chemical class Mode of action Application timing
organophosphate interferes with cell division and inhibits rooting. preemergence

Controls annual bluegrass, crabgrass, goosegrass, henbit, lambsquarters, and yellow foxtail. Provides excellent control of annual bluegrass. Strongly adsorbed to soil, potential for leaching is very low.

bentazon

Chemical class Mode of action Application timing
benzothiadiazole inhibits photosynthesis, causes cell membrane destruction postemergence

Controls primarily yellow nutsedge; will provide control of broadleaf weeds including Canada thistle, groundsel, ladysthumb, lambquarters, Pennsylvania smartweed, purslane, shepard’s purse and yellow woodsorrel.

Controls primarily yellow nutsedge; will provide control of broadleaf weeds including Canada thistle, groundsel, ladysthumb, lambquarters, Pennsylvania smartweed, purslane, shepard’s purse and yellow woodsorrel.

Contact herbicide. Some temporary turf discoloration may occur. The addition of a surfactant is required for application. Bentazon is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

bispyribac-sodium

Chemical class Mode of action Application timing
pyrimidinyloxybenoic inhibition of amino acid synthesis postemergence

Controls annual bluegrass and roughstalk bluegrass in creeping bentgrass and perennial ryegrass, also broadleaf plantain, common chickweed, dandelion, henbit, narrowleaf plantain, white clover and yellow woodsorrel.

May injure Kentucky bluegrass, especially some cultivars. Labeled for use only on golf courses and sod fields.

carfentrazone

Chemical class Mode of action Application timing
protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes postemergence

Controls a wide range of broadleaf weeds.

Often formulated in pre-mixed combinations with other broadleaf herbicides. Does not provide good control of perennial broadleaves when applied alone. Provides good moss control. Does not persist in soil and has no leaching potential.

chlorsulfuron

Chemical class Mode of action Application timing
sulfonylurea inhibition of amino acid synthesis postemergence

Controls tall fescue, annual ryegrass and perennial ryegrass in Kentucky bluegrass, fine fescue and bentgrass; also buttercup, cinquefoil, common chickweed, common mallow, henbit, mouse-ear chickweed, pineappleweed, prostrate knotweed, purslane, shepards-purse, white clover, wild garlic and wild violet.

clopyralid

Chemical class Mode of action Application timing
pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence

Broad spectrum; controls many broadleaves, particularly effective on members of the aster family (dandelion and hawkweed) and bean family (clover, black medic and birdsfoot trefoil). Translocated within the plant.

Herbicide products that contain clopyralid are Restricted Use on residential turf. Turf clippings from treated areas should not be collected for mulching and composting or sent to a recycling facility. Use caution near ornamentals, including aster, daisy, coneflower, liatris, redbud, and honeylocust. Clopyralid is weakly adsorbed to soil and has a moderate leaching potential.

corn gluten meal

Chemical class Mode of action Application timing
not classified inhibition of root growth at germination. preemergence

Labeled for the control of crabgrass species.

Corn gluten meal is a by-product of the wet-milling of corn grain for the production of corn starch and corn syrup. Because of its high protein content (about 60% by weight), its historic use has been as an animal feed. Its associated nitrogen concentration of about 9 to 10% N makes it a fertilizer. The carrier of the nitrogen is the proteinaceous fraction of the corn grain; several dipeptides in this fraction comprise the active ingredient that imparts some preemergence herbicidal activity. Research suggests that the herbicidal activity is greater in dry environments than in areas where soil moisture for plant growth is adequate. Product application rates for turf are 10 to 20 lbs of corn gluten meal per 1000 ft2 applied twice a year (equal to approximately 2 to 4 lbs of N per 1000 ft2 per year) with some products suggesting higher rates. Studies conducted at the University of Massachusetts indicate that crabgrass control using corn gluten provided no advantage over maintaining a properly fertilized lawn regardless of whether the fertilizer material used was organic or synthetic. Corn gluten is considered to be organic.

dicamba

Chemical class Mode of action Application timing
benzoic acid disrupts growth by mimicking naturally occurring plant hormones. postemergence

Controls many broadleaf weeds, especially red sorrel, dandelion, violets, plantains, chickweed, ground ivy, buttercup and woodsorrel.

Formulated alone and in premixed combinations with other broadleaf herbicides. Susceptible weeds curl and twist soon after application. Drift to desirable plants, particularly flowers, ornamentals, and other broadleaf plants should be prevented. Dicamba leaches readily into the soil and is soil active, therefore applications within the drip line of trees should be avoided.

dimethenamid

Chemical class Mode of action Application timing
chloroacetanilide/chloroacetamide inhibits very long chain fatty acid synthesis preemergence

Controls annual bluegrass, crabgrass, downy brome, yellow foxtail, fall panicum, sandbur, bittercress, carpetweed, lambsquarters, pigweed, puslane, common ragweed, shepherd’s-purse, spurge, willowherb, kyllinga and yellow nutsedge.

Dimethenamid is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

dithiopyr

Chemical class Mode of action Application timing
pyridine inhibits cell division. preemergence

Controls annual grasses, including annual bluegrass, barnyardgrass, crabgrass, downy brome, yellow foxtail and sandbur. Also provides preemergence control of several broadleaf weeds including bittercress, carpetweed, henbit, black medic, pineappleweed, purslane, shepard’s-purse, corn speedwell, spurge, yellow woodsorrel and creeping woodsorrel. Enters the plant through shoots and roots.

Also provides early postemergence crabgrass control when applied before the 3-leaf growth stage.

ethofumesate

Chemical class Mode of action Application timing
not classified unkown, evidence suggests inhibition of leaf wax formation. preemergence and postemergence

Utilized primarily in turf for postemergence control of annual bluegrass. Absorbed by emerging roots and shoots, and is translocated to leaves. Postemergence applications are somewhat poorly absorbed by leaves with thick, well-developed cuticles.

Also provides preemergence control of barnyardgrass, common chickweed, crabgrass, purslane and yellow foxtail, and some yellow nutsedge suppression. Ethofumesate is not prone to leaching.

fenoxaprop-ethyl

Chemical class Mode of action Application timing
aryloxyphenoxyprionate inhibits biosynthesis of fatty acids in sensitive plants postemergence

Controls annual grassy weeds, especially large and smooth crabgrass, goosegrass, barnyardgrass, yellow foxtail, sandbur and Japanese stiltgrass.

Application rate depends on weed growth stage. Some broadleaf herbicides when tank-mixed with or applied within a certain period of time can reduce the efficacy of fenoxprop as a result of herbicide antagonism. Can be tank-mixed with preemergence crabgrass herbicides to obtain residual control. Drought stress can significantly reduce efficacy. No soil activity.

ferric-HEDTA

Chemical class Mode of action Application timing
not classified iron toxicity postemergence

Ferric-HEDTA is a selective broadleaf herbicide. It is effective at cooler temperatures, rain-fast in a short period of time and results can be seen in as little as 24 to 48 hours.

Ferric-HEDTA is quickly absorbed by the leaf tissue and transported down to the root. The leaf tissue turns black or brown and death the of the weed follows.

forasulam

Chemical class Mode of action Application timing
sulfonanalide inhibits biosynthesis of certain essential amino acids postemergence

Controls bedstraw, common chickweed, mouse-ear chickweed, white clover, dandelion, dandelion, fleabane, groundsel, prostrate knotweed, shepherd’s-purse and spurge.

fluroxypyr

Chemical class Mode of action Application timing
pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence

Broad-spectrum material, especially effective for chickweed, cinquefoil, creeping woodsorrel, dandelion, ground ivy, henbit, plantain, purslane, white clover, wild strawberry, and yellow woodsorrel.

Either formulated alone and in pre-mixed combinations with other broadleaf herbicides. Absorbed by roots and shoots and is strongly translocated within the plant. Induces an epinastic (leaf curling) response and death occurs in days or weeks.

glufosinate-ammonium

Chemical class Mode of action Application timing
not classified causes metabolic changes that disrupt photosynthesis. postemergence

Glufosinate-ammonium is a non-selective herbicide.

Not translocated. Often poor to fair control of some perennial weeds. No soil activity.

glyphosate

Chemical class Mode of action Application timing
phosphonoglycine inhibits biosynthesis of certain essential amino acids postemergence

Glyphosate is a non-selective herbicide.

Strongly translocated and therefore very effective for perennial weeds. Symptoms include yellowing, starting with the youngest plant tissue, and progressing toward the oldest. Binds strongly to soil and does not leach. Glyphosate is not soil active.

halosulfuron

Chemical class Mode of action Application timing
sulfonylurea inhibits biosynthesis of certain essential amino acids postemergence

Halosulfuron is utilized in cool-season turf primarily for the control of yellow nutsedge.

Yellow nutsedge is best treated in the three- to eight-leaf stage of growth. The addition of a non-ionic surfactant is required. Halosulfuron is degraded by microbial activity in the soil and has a low potential for leaching.

isoxaben

Chemical class Mode of action Application timing
amide inhibits the biosynthesis of cellulose, disrupts root and hypocotyl development. preemergence

Controls a wide range of broadleaf weeds including black medic, carpetweed, dandelion, henbit, plantain, purslane, red sorrel, spurge, white clover, and yellow woodsorrel.

The only compound available exclusively for preemergence control of broadleaf weeds in cool-season turf.

mesotrione

Chemical class Mode of action Application timing
triketone disrupts carotenoid synthesis. preemergence and postemergence

When applied postemergence, mesotrione controls many broadleaf weeds including broadleaf plantain, carpetweed, common chickweed, clover, henbit, horseweed, purslane, purslane speedwell and yellow woodsorrel. Will provide postemergence control of creeping bentgrass, nimblewill, and yellow nutsedge as well. Also indicated for preemergence control of barnyardgrass, crabgrass, yellow foxtail and broadleaf annual weeds. Can be applied at the time of cool-season turf establishment for preemergence control. Symptoms in susceptible weeds include bleaching followed by necrosis.

Mesotrione is a synthetic analogue of the alleochemical leptospermone, which is produced by the roots of the “bottle brush” plant (Callistemon citrinus). Classified as a Reduced Risk pesticide by the US Environmental Protection Agency (EPA), for information visit https://www.epa.gov/.

oxadiazon

Chemical class Mode of action Application timing
protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes. preemergence

Primarily controls annual grasses (barnyardgrass, crabgrass and goosegrass) but also controls several broadleaf weeds (bittercress, carpetweed, smartweed, spurge, yellow woodsorrel).

Strongly adsorbed by soil colloids and therefore is not prone to leaching.

pendimethalin

Chemical class Mode of action Application timing
dinitroaniline interferes with cell division preemergence

Primarily used for preemergence control of crabgrass and other annual grasses including barnyardgrass, annual bluegrass, yellow foxtail, goosegrass and sandbur.  Also controls several broadleaf weeds including carpetweed, common chickweed, henbit, prostrate knotweed, purslane, spurge and yellow woodsorrel.

Pendimethalin is not prone to leaching

penoxsulam

Chemical class Mode of action Application timing
sulfonamide inhibits biosynthesis of certain essential amino acids. postemergence

Controls bittercress, broadleaf plantain, chickweed, dandelion, ground ivy, white clover and yellow wood sorrel.

Formulated alone and in combination with other selective herbicides on fertilizers and straight granules. Accepted for review and registration under the Reduced Risk Pesticide Initiative of the US Environmental Protection Agency (EPA), for information visit https://www.epa.gov/.

phenoxy herbicides (2,4-D, 2,4-DP/dichlorprop, MCPA, MCPP/mecoprop)

Chemical class Mode of action Application timing
growth regulator disrupt growth by mimicking naturally occurring plant hormones. postemergence

The phenoxy herbicides control a wide range of broadleaf weeds.

Systemic herbicides, but relatively slow acting. General symptoms on susceptible weeds include the twisting and curling of leaves and stems soon after application. Avoid application in hot weather. Products containing 20% or more 2, 4-D are classified as Restricted Use in Massachusetts. MCPA is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

prodiamine

Chemical class Mode of action Application timing
dinitroaniline interferes with cell division. preemergence

Provides preemergence control of crabgrass, goosegrass, annual bluegrass and other annual grasses. Also controls several broadleaf weeds including carpetweed, chickweed, henbit, purslane, spurge and yellow woodsorrel.

Low water solubility and is strongly adsorbed to soil, therefore not prone to leaching.

pyraflufen-ethyl

Chemical class Mode of action Application timing
phenylpyrazole inhibits chlorophyll production, results in rapid destruction of cell membranes. postemergence

Controls carpetweed, chickweed, curly dock, dandelion, pineappleweed, purple deadnettle, purslane, round mallow, smartweed and spurge.

Contact herbicide. Formulated alone and in premixed combinations with other broadleaf herbicides.

quinclorac

Chemical class Mode of action Application timing
quinoline carboxylic acid unknown, thought to inhibit cell wall biosynthesis and mimic natural plant hormones. preemergence and postemergence

When applied postemergence, provides control of crabgrass, yellow foxtail, barnyardgrass, white clover, black medic, dandelion and speedwell. Also provides preemergence control of crabgrass and other annual grasses. Does not control goosegrass. Absorbed by foliage and roots and is translocated throughout the plant.

Formulated alone and in premixed combinations with other broadleaf herbicides. Postemergence treatments require addition of a methylated seed oil, crop oil concentrate or high quality surfactant for best control. Can be used before or after seeding or overseeding of cool-season turfgrasses for the control of crabgrass and other annual grasses. This compound should be used to control crabgrass before the 2-tiller and after the 5-tiller stage of growth.

siduron

Chemical class Mode of action Application timing
substituted urea root growth inhibitor; disrupts cell division. preemergence

Controls barnyardgrass, crabgrass, downy brome, and yellow foxtail. Does not control annual bluegrass, chickweed, clover, goosegrass and plantain.

Either formulated alone or on turf starter fertilizers. Unlike many other preemergence herbicides, siduron can be applied at time of seeding, on seedling turf and on sod to be harvested.

sulfentrazone

Chemical class Mode of action Application timing
protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes. preemergence and postemergence

Provides postemergence control of broadleaf weeds including carpetweed, common chickweed, mouse-ear chickweed, dandelion, henbit, lambquarters, narrowleaf plantain, Pennsylvania smartweed, purslane, spurge, star-of-bethelem, speedwell, yellow woodsorrel and creeping woodsorrel. Can be used to control or suppress yellow nutsedge and kyllinga.

Formulated alone and in premixed combinations with other broadleaf herbicides. Sulfentrazone is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

topramezone

Chemical class Mode of action Application timing
pyrazolones disrupts carotenoid synthesis. postemergence
Provides effective control of barnyardgrass, large and smooth crabgrass, yellow foxtail,  fall panicum and Japanese stiltgrass. Very effective on goosegrass.

triclopyr

Chemical class Mode of action Application timing
pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence

Provides effective control of poison ivy, ground ivy, wild violets, and other difficult-to-control perennial weeds. Absorbed by roots and shoots and readily translocated throughout the plant.

Formulated alone and in premixed combinations with other broadleaf herbicides. The potential for leaching decreases with increasing soil organic matter and when conditions are favorable for soil microbial activity.

Table 12. Common herbicide products and their active ingredients

Herbicide product Active ingredient(s)
Acclaim Extra fenoxaprop-p-ethyl
Armor Tech CGC (40 & 40WP) dithiopyr
Armor Tech Quin Pro 75DF quinclorac
Balan 2.5G benefin
Barricade (4FL, 65WG, on-fertilizer formulations) prodiamine
Basagran T&O bentazon
Bensumec 4LF bensulide
Calvalcade PQ prodiamine and quinclorac
Cavalcade 65WDG prodiamine
Defendor florasulam
Dimension (2EW, EC, Ultra 40WP, on-fertilizer formulations) dithiopyr
Dismiss sulfentrazone
Drive (75DF, XLR8) quinclorac
Echelon 4SC prodiamine and sulfentrazone
Eject 75DF quinclorac
Fiesta ferric HEDTA
Finale glufosinate
Gallery isoxaben
Guardrail 65WDG prodiamine
Halosulfuron Pro halosulfuron
Jewel oxadiazon
Kade 65 WDG prodiamine
Knighthawk prodiamine
Manage halosulfuron
Pendulum (2G, 3.3EC, AquaCap) pendimethalin
PoaConstrictor ethofumesate
Pre-M (3.3EC, Aqua-Cap, on-fertilizer formulations) pendimethalin
Pre-San Granular (7G, 12.5G) bensulide
PrimeraOne Prodiamine 65WDG prodiamine
PrimeraOne Quinclorac 75DF quinclorac
PrimeraOne Prodiamine 65WDG prodiamine
Proclipse 65WDG prodiamine
Prograss ethofumesate
Prograss SC ethofumesate
Pylex topramezone
Quali-Pro Dithiopyr 40WSB dithiopyr
Quali-Pro Prodiamine 65WDG prodiamine
Quali-Pro Quinclorac 75DF quinclorac
Quin Pro quinclorac
Resolute (4L, 65WDG) prodiamine
Resolute (65WG, 4L) prodiamine
Ronstar (50WSP, FLO, G) oxadiazon
Ronstar G oxadiazon
Scythe pelargonic acid
SedgeHammer halosulfuron
SedgeHammer+ halosulfuron
Stonewall 65WDG prodiamine
Stonewall RQ prodiamine and quinclorac
Team (2G, Pro) benefin and trifluralin
Tenacity mesotrione
Tower dimethanamid
Tupersan siduron
Velocity SG bispyribac-sodium
Xonerate amicarbazone